Windows 7 RC and Windows Server 2008 R2 RC (builds 7100) will be made available for download to TechNet and MSDN subscribers on 30 April 2009 and on 5 May 2009, will be available for general download.

Just remember, unless you download it from Microsoft, you can’t be guaranteed that it is the actual RC, and that nothing “extra” is included. Be safe, don’t download software from un-trusted sources.